US President Barack Obama vowed Saturday to help rescue thousands of civilians besieged by jihadists on an Iraqi mountain, as an MP warned they would not survive much longer.

He gave no timetable for the first US operation in Iraq since the last American troops withdrew three years ago and put the onus on Iraqi politicians to form an inclusive government and turn the tide on jihadist expansion.

“The United States can’t just look away. That?s not who we are. We’re Americans. We act. We lead. And that’s what we’re going to do on that mountain,” Obama said.

US and Iraqi aircraft have air dropped food and water to the thousands of people, many of them members of the Yazidi minority, who have been stranded on Mount Sinjar since they fled Islamic State attacks on their homes a week ago.

Obama said he had received “strong support” from British Prime Minister David Cameron and French President Francois Hollande, who had both agreed to provide humanitarian assistance.

Amid reports that the children and elderly among them were already dying, Obama justified the decision to intervene Thursday with the risk of an impending genocide against the Yazidis.

Yazidi MP Vian Dakhil, whose poignant appeal in parliament this week made her the public voice of her community, said time was running out.

“We have one or two days left to help these people. After that they will start dying en masse,” she told AFP Saturday .

The Yazidis, who worship a figure associated with the devil by many Muslims, are a small and closed community, one of Iraq’s most vulnerable minorities.

– Pressure on Maliki –

After a first day of US air raids on fighters who had moved within striking distance of Kurdistan, a top official in the autonomous region said the time had come for a fightback.

“Following the US strikes, the peshmerga will first regroup, second redeploy in areas they retreated from and third help the displaced return to their homes,” Fuad Hussein told reporters Friday in the Kurdish capital Arbil.

The first US bombings struck IS positions and at least one convoy of vehicles carrying militants west of Arbil.

Obama said he had authorised the strikes in Iraq to protect US personnel serving there. “And, if necessary, that’s what we will continue to do,” he said Saturday.

Federal and Kurdish officials, who had been at loggerheads since IS fighters launched their an offensive exactly two months ago that has brought Iraq to the brink of partition, have said they were now working together and with US advisers.

But it remained unclear how much longer and deeper inside Iraq US warplanes would intervene and Obama stressed the real game-changer would be the much-delayed formation of an inclusive government.

“The most important timetable I’m focused (on) now is the Iraqi government getting formed and finalised, because in the absence of an Iraqi government, it is very hard to get a unified effort by Iraqis against” IS, he said.

– Dehydration –

Many Iraqis see Prime Minister Nuri al-Maliki as partly responsible to entrenching sectarianism and providing IS with a fertile ground in Sunni areas.

He won April elections comfortably but the militant onslaught launched in June ahs been his position untenable.

Washington, Tehran, the Shiite religious leadership and much of his own party have pulled their support but has dug his heels in and apparently not yet given up on seeking a third term.

Grand Ayatollah Ali al-Sistani, Iraq’s most revered Shiite cleric, on Saturday alluded to Maliki when he complained “there were some people who do not want the good of the country.”

He was being quoted, after a meeting in the city of Najaf, by Chaldean Catholic Patriarch Louis Sako, whose community was displaced on an unprecedented scale this week.

Up to 100,000 Christians were forced to flee from their homes in a matter of hours on Thursday, completely emptying the country’s largest Christian city Qaraqosh of its population.

Among the hundreds of thousands of people who fled their homes in northern Iraq were several other minorities such as the Shabak and Turkmen Shiites.

UNESCO chief Irina Bokova called it an “emerging cultural cleansing”.

“The US should strike Sinjar, even if there are civilian casualties. It’s better than letting everyone die,” the Yazidi MP, Vian Dakhil, said.

Obama said he was confident the US could prevent IS fighters “from going up the mountain and slaughtering the people who are there” but added the next step of creating a safe passage was “logistically complicated”.

The International Rescue Committee (IRC) is providing emergency care to around 4,000 people who crossed safely into neighbouring Syria.

“They suffer from dehydration, sunstroke and some of them are seriously traumatised,” the IRC’s Suzanna Tkalec told AFP, adding that many had walked all day for several days.